PILOT-FISH. 



365 



is edible. The genus is represented in the Monte Bolca Eocene. Horse-mackerel 

 sometimes make their appearance in enormous shoals on the British coasts ; and it 

 is stated that on one occasion upwards of ten thousand were taken in Cornwall. 

 A correspondent of Yarrell wrote, that in the summer of 1834 vast shoals of these 

 fish were seen on the Glamorganshire coast. " They were first observed in the 

 evening, and the whole sea, as far as we could command it with the eye, seemed in 

 a state of fermentation with their numbers. Those who stood on some projecting 

 rock had only to dip their hands into the water, and with a sudden jerk they 

 might throw up three or four. The bathers felt them come against their bodies, 

 and the sea, looked on from above, appeared one dark "mass offish. Every net was 

 immediately put in requisition ; and those which did not give way from the weight, 

 were drawn on shore laden with spoil. One of the party who had a herring-seine 

 with a two-inch mesh was the most successful ; every mesh held its fish, and 

 formed a wall that swept on the beach all before it. The quantity is very inade- 



PILOT-FISH. 



Pilot-Fish. 



quately expressed by numbers, they were caught by cart-loads. As these shoals 

 were passing us for a week, with their heads directed up channel, we had the 

 opportunity of noticing that the feeding-time was morning and evening. They were 

 pursuing the fry of the herring, and I found their stomachs constantly full of them." 

 Another genus is represented by the pelagic pilot-fish (Naucrates 

 ductor), which takes its name from a supposed habit of guiding and 

 protecting the sharks and ships which it accompanies. Having no plates on the 

 lateral line, this fish is further characterised by the rounded under surface of the 

 body, by the first dorsal fin being composed in the adult of detached spines, by the 

 absence of finlets, and the presence of a keel on each side of the tail. When adult, 

 the pilot-fish measures about a foot in length. In colour it is bluish, with five or six 

 dark vertical bands ; the tail-fin sometimes having the ends of its two lobes dark, 

 as also a band across the middle third. Ranging over all temperate and tropical 

 seas, pilot-fish were regarded as sacred by the ancients, by whom they were known 

 as pompili ; the common belief being that when the ship neared land, the fish 

 suddenly disappeared, and thus gave warning to the sailors of impending danger. 

 Many legends have grown in later times as to how pilot-fish will prevent sharks 



